Commercial passenger aircraft commonly include a pressurized fuselage having a main upper deck for carriage of passengers and a lower deck exclusively for carriage of cargo during commercial flights. These cargo compartments are typically closed off areas located within the lower fuselage underneath the passenger deck floor. Such cargo compartments are traditionally filled with bulk cargo, which refers to any cargo that is not containerized, such as passenger suitcases manually loaded by baggage handling personnel into the cargo compartment. Many large aircraft employ quick loading containers known as Unit Load Devices (ULDs). A ULD is a container used to load luggage, freight, mail, or similar containerized items on wide-body aircraft and certain narrow-body aircraft. The ULDs allow for a large quantity of cargo to be bundled into a single unit, which leads to fewer load units and saves ground crews time and effort when loading the cargo compartment of the aircraft. Netted cargo pallets with defined base structure geometries are also specialized types of ULDs.
Cargo compartments include a ceiling, which corresponds to the passenger deck floor, and a floor which may be flat or curved to match the bottom contour of the fuselage. The floor of the cargo compartment typically includes rollers, power rollers, or ball mats to provide for movement of large cargo containers within the cargo compartment. This configuration requires a large number of rollers, stops, and locks on the floor surface in order to utilize and safely support cargo containers. Cargo compartments having floors that lack such rollers are not suitable for loading and carrying large cargo containers, and are provided on some aircraft to accommodate “bulk cargo,” such as manually loaded passenger baggage. Furthermore, the roller floors require the containers to be manually moved and positioned at a desired storage location within the cargo compartment.
Accordingly, those skilled in the art continue with research and development efforts in the field of container loading of aircraft cargo compartments.